Segmented Cellular Wheel for Pressure Wave Supercharger
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Solution Overview
Problem
The production of cellular wheels for pressure wave superchargers with small cell wall thicknesses is challenging due to high material and processing costs, and existing methods lead to crack formation and failure under thermal stress.
Innovation Solution
Incorporating incisions between adjacent slats on the intermediate sleeve, allowing for elastic movement and reducing stress buildup, and using a labyrinth seal design with annular gaps to maintain performance and prevent material damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If cell wall thickness is reduced to 0.4 mm or less to achieve maximum cell volume and reduce weight, then productivity and weight are improved, but manufacturing precision and reliability deteriorate due to difficulty in producing dimensionally stable cellular wheels and crack formation under thermal stress
Solution Approach 1:
The cellular wheel is segmented into multiple sleeves (outer sleeve, inner sleeve, intermediate sleeves) joined by slats. This segmentation allows each component to be manufactured separately with standard thicknesses, avoiding the difficulty of producing thin-walled cellular wheels as a single piece while maintaining overall lightweight design.
Solution Approach 2:
The slats are designed to be elastically deformable, allowing dynamic adjustment of the cellular wheel structure under thermal stress. This elasticity enables the wheel to accommodate thermal expansion and contraction without cracking, maintaining reliability while using thinner wall sections for weight reduction.
2Manufacturing precision
If Z-shaped profiles are lined up and fixed in precise positions to form chambers, then manufacturing precision is improved, but device complexity and production time increase significantly
Solution Approach 1:
Multiple slats and sleeves are merged into an integrated modular structure where components are joined together to form the cellular wheel. This merging reduces the number of separate assembly operations compared to lining up individual Z-profiles, simplifying manufacturing while maintaining precision through the modular design.
3Ease of manufacture
If erosion process is used to produce cellular wheel from solid body, then manufacturing flexibility is improved, but material consumption and processing costs increase
Solution Approach 1:
Instead of eroding a solid body, the cellular wheel is segmented into discrete sleeves and slats that can be manufactured separately using more material-efficient processes. This segmentation reduces material waste compared to subtractive erosion while maintaining manufacturing flexibility through modular assembly.
4Temperature
If rapid temperature changes occur inside cellular wheel causing thermal expansion and contraction, then thermal response is improved, but reliability deteriorates due to crack formation in joining areas
Solution Approach 1:
The slats are designed with elastic properties that allow them to dynamically respond to thermal expansion and contraction forces. This dynamic flexibility enables the cellular wheel to accommodate rapid temperature changes without generating the stress concentrations that lead to crack formation at joining areas.
Solution Approach 2:
The elastic design of the slats provides beforehand cushioning against thermal stress by allowing controlled deformation before stress can build up to crack-causing levels. This preemptive flexibility protects the joining areas between slats and sleeves from thermal fatigue damage.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables the production of mechanically stable cellular wheels with reduced stress and material damage, maintaining performance and reducing costs while preventing crack formation and improving thermal stability.
Implementation Method 1
The incisions arranged in the intermediate sleeve provide an edge strip for the corresponding lamella, which is designed to be elastically movable with respect to the intermediate sleeve and other edge strips and advantageously compensates for the deformation of the lamellae caused by temperature fluctuations by moving the edge strip in a substantially radial direction.
Implementation Method 2
outer sealing sleeves overlapping the outer sleeve and joined to the outer sleeve with a sealing profile for a labyrinth seal
Data Source
Figure 1~3
Figure 4~8
Figure 9~14
AI summary
The cellular wheel (10) is made of metal and has an outer sleeve (12) arranged coaxial to a rotational axis, an inner sleeve (14) arranged coaxial to the outer sleeve and an intermediate sleeve (18) arranged between and coaxial to the outer sleeve and the inner sleeve. The outer sleeve, the inner sleeve and the intermediate sleeve or one of the intermediate sleeves have notches (26) between adjacent fins (16), where the notches extend from the two end faces of the cellular wheel.